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Full-Text Articles in Engineering
Some Aspects Of Process Control In Semiconductor Manufacturing, Keelin Relihan, Shane Geraghty, Aidan O'Dwyer
Some Aspects Of Process Control In Semiconductor Manufacturing, Keelin Relihan, Shane Geraghty, Aidan O'Dwyer
Conference papers
This paper outlines some aspects of process control in semiconductor manufacturing. Starting with an outline of the semiconductor manufacturing process, the contribution will discuss temperature control of the chemical vapour deposition stage and the control of the wafer etching process, based on the industrial experience of the first two authors. Subsequently, the authors draw the attention of the semiconductor manufacturing community to the potential of properly tuned PID controllers for the achievement of simple and high performance control solutions.
A Case Study In Modeling And Process Control: The Control Of A Pilot Scale Heating And Ventilation System, Robin Mooney, Aidan O'Dwyer
A Case Study In Modeling And Process Control: The Control Of A Pilot Scale Heating And Ventilation System, Robin Mooney, Aidan O'Dwyer
Conference papers
This paper details the control of a pilot scale laboratory heating and ventilation system. The system is represented in 2x2 multi-input, multi-output (MIMO) form. A process reaction curve identification technique was used to model (in first order lag plus delay - FOLPD - form) the flow process and temperature process portions of the system, over a range of operating conditions. Tests revealed that both processes were continuously non-linear. A gain scheduler with static decoupling was designed, using look-up tables, to continuously interpolate for the most suitable proportional-integral (PI) or proportional-integral-derivative (PID) controller settings and decoupler gains. The contribution of this …
Smith Predictor Structure Stability Analysis Using Mikhailov Stability Criterion, Pauline Sourdille, Aidan O'Dwyer, Eugene Coyle
Smith Predictor Structure Stability Analysis Using Mikhailov Stability Criterion, Pauline Sourdille, Aidan O'Dwyer, Eugene Coyle
Conference papers
As is well known, stability is an important requirement for control systems. Due to the nature of time-delay processes, common methods to evaluate stability may be difficult to use. In 1938, Mikhailov proved a frequency response criterion, which is sufficient and necessary for the stability of processes described by known n-th order constant coefficient linear differential equations. This paper presents the Mikhailov method and the application of this method to a Smith predictor structure controlled by a PI controller.
Implementation Of New Modified Smith Predictor Designs, Pauline Sourdille, Aidan O'Dwyer
Implementation Of New Modified Smith Predictor Designs, Pauline Sourdille, Aidan O'Dwyer
Conference papers
This paper outlines two modified Smith predictors developed previously by the authors and then presents the implementation results of these structures for the control of a pilot scale heating and ventilation system, the PT 326 process trainer from Feedback Instruments Ltd. These results are compared to the results obtained with a Smith predictor structure.
New Modified Smith Predictor Designs, Pauline Sourdille, Aidan O'Dwyer
New Modified Smith Predictor Designs, Pauline Sourdille, Aidan O'Dwyer
Conference papers
By combining several existing modified Smith predictor structures, presented in a literature review, a generalised form of the Smith predictor is proposed. From this structure, excellent servo and regulator responses can be obtained by specifying three controller dynamic elements. Two new modified Smith predictor structures are presented with their associated tuning rules. The results of the simulations indicate that the two new designs give better overall responses than the original Smith predictor.